Magnetic engine starter



Dec. 27, 1927. 1,653,618

0. BRISBOIS MAGNETIC ENGINE STARTER Filed June 14. 1924 2 Sheets-Sheet 1 :Z TZJ 21 0 1111mm||11m11 Z2 Z3 lillllllfil i! 5 it i /9 0/1 1 4 I 5: l E

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0. BRISBOIS MAGNETIC ENGINE STARTER Dec. 27, 1927.

Filed Junel4, 1924 2 Sheets-Sheet 2 VE' I13 041 z 6077157 125 his I n Patented Dec. 27, 1927.

UNITED *STATES ODILON BRISIBOIS, OF CHICAGO, ILLINOIS.

MAGNETIC ENGINE STARTER. I

. Application filed June 14, 1924. Serial No. 720,033.

This invention relates to a'magnetic engine starter of that type in'which the magnetic flux is utilized for shifting a normally displaced armature for bringing a driving member such as a pinion carried thereby into engagement with a driven member, such as a gear upon the fly wheel of'an engine and is an improvement of the starter shown in my co-pending application Serial No. 667,- 103, filed October 8th, 1923.

It is an object of this invention to provide for the absorption of the shock that occurs between the driven member'and driving member when the engine starts under its own power; and to provide for the proper demeshing of the driving member to prevent objectionable chamfering thereof. To this end, it is a more specific object of this invention to provide a driving member that has relative movement with respect to the armature and that is confined between a pair of cushions or yielding abutments.

With these and other objects int-view which will become more apparent in the following description and disclosures, this invention comprises the novel structure and combinations hereinafter described and more particularly pointed out and defined in the appended claims,

In the accompanying drawings which il lustrate a preferred embodiment of this invention and in which similar'reference nu.- merals refer to similar featuresin the different views 4 Figure 1 is a longitudinal sectional view through the starter showing parts in elevation.

Figure 2 is a view similar to Figure 1 showing parts in different positions.

Figure 3 is a reduced elevational view of the starting motor.

Figure 4 is a front elevational view of the same. 1 I

Figure 5 is an enlarged sectional view through the controlling mechanism for the brush holder. I

Figure 6 is a sectional'view upon the line 6-6 of Figure 2.

Figure 7 is a sectional view upon the line 77 of Figure 2. a

As shown on the drawings:

Referring now to the drawings, there is shown a motor comprising a casing 1 having a removable'rear hood 2 or the like. The front end of the casing consists of a removable head'or plate having an elon gated bearingsleeve 3 through which the armature shaft 13 projects. The armature is shown at 4 surrounded by the usual field 5 and provided with the commutator 6 upon its rear end.

Secured to the rear end of the hood 20f the motor casing is a hollow drum 7 protation and sliding movements with respect 1 thereto. This drum 9 is provided with a stud 10 that projects into the helical slot 8. A brush holder 11 in the form of a fiat ring is bolted or secured to the forward end of the second drum 9. A plurality of commutator brushes 12 are supported u on this ring 11' and yieldingly bear upon t e commutator 6 through the springs 12. The

armature shaft 13 (Figure 5) extends into the drum 9 and it is provided with a collar 14 spaced slightly from the rear end of the armature 4. The brush holding ring 11 is confined between said collar 14: and armature. Consequently the drum 9 and brush holder are compelled to partake of the longitudinal movements of the armature; they are however capable of relative rotation with respect to the armature.

A pinion 15 provided with an elongated hub or sleeve 16 is mounted upon the forward end of the armature shaft 13 for limited relative rotation and longitudinal movement with respect thereto. This sleeve or hub extends into the bearing sleeve 3 of the motor casing and is suitably journalled therein. A thrust bearing 17 issecured in the front end of-the sleeve to receive the impact of the pinion thereagainst.

The sleeve 16 is provided with a slot 18. This slot slopes forwardly from its rear end in the direction of rotation of the armature shaft at substantially an angle of 45 with respect to the axis of the armature shaft. The armature shaft 13 is provided with a stud 19 that normally rests substantially midway of the slot 18 as shown in Figure 1, and provides a lost motion connection with the sleeve and shaft for limited relative longitudinal and rotary motion. The

particular direction of the slope of the slot 18 is important in controlling the pinion 15 as will later more full appear.

A screw 20 is secure in the forward end of the armature shaft and a head 21 on this screw confines a strong coil spring 22 against the pinion 15. A. similar coil s ring 22 is confined between the forward en of the armature and the rear end of the sleeve 16. Consequentl on account of the pin and slot connection between the sleeve and motor shaft, the sleeve is yieldingly confined between the two cushion springs 22, the funcarmature coils being reversed. This will tend to neutralize the rotation efiect upon the armature. Consequently when the motor is started from the position shown in Figure 1 which is the inoperative position of the motor, there will be greatly diminished rotative torque. In the position shown in Figure 1, the armature is also normally displaced rearwardly of its field. Consequently when the motor is started, it will be drawn into its field by the magnetic flux, and on account of the displacement of the brushes, it will rotate more slowly while moving longitudinally. When the stud 10 reaches the forward end of the slot 8, the brushes will be in their proper positions upon the neutral axis of the motor.

The operation is as follows:

When the motor is started from the osition shown in Figure 1, the magnetic orce will draw the armature forwardly to mesh the pinion 15 with the fly wheel gear 23. The rotation of the armature will be in an anti-clockwise direction viewing the rear end thereof. Conse uently as the stud 10 and the drum 9 whic is in reality a part of the brush holder is constrained to follow the course of the helical slot 8 which slopes in a direction opposite to the direction of rotation of the armature, the brushes 12 will also rotate over the commutator in such opposite direction and exercise a braking action for impeding the rotation. Obviously the initial rotation of the armature is retarded by both the effect of the displaced brushes and their braking action upon the commutator.

The magnetic flux will draw the armature forwardly and bring the pinion 15 into meshing relation with the fly wheel gear 23 as shown in Figure 2. At this time, the stud men the drum 9 will be in the forward end of the slot 8 which extends longitudinally to the axis of the motor for a short distance,

or in other words might be said to be parallel to such axis. This longitudinally extending end of the slot 8 is for the purpose of retaining the stud 10 and preventing the same from moving backward during the starting-operation of the motor.

WVhen the pinion 15 picks up the load arising from starting the fly wheel gear 23, there will be relative longitudinal movement between the hub 16 and motor shaft 13, the hub 16 and gear 15 will be moved rearwardly into the dotted line position shown in Figure 2. This rearward movement of hub 16 will hence absorb the shock and impact of the cranking load and in effect impart a cranking yield to the starter.

In the past, there has always been more or less of a sudden shock or impact between the fly wheel gear and the starting inion when the former starts to run un er its own power. Such shock or impact is substantially eliminated in the present structure for the reason that when the fly wheel gear starts to rotate under its own power and drives the pinion, the latter can rotate relatively to the motor shaft, and during such relative rotation, it will move forward longitudinally for compressing the end spring 22. This will shift the sleeve so that the stud 19 will be slightly below the middle or neutral position of the slot 18. If the motor circuit is now opened, the usual oscillations of the armature as it is being driven by the fly wheel gear will dislodge the stud 10 from the longitudinally extending end of the slot 8. When this has been done, the stud 10 will travel rearwardly in said slot 8 since the friction between the brushes and the commutator will cause the drum 9 to revolve with the armature. Consequently this movement of the stud 10 to the rear end of the slot 8 will decenter the armature to its normal position as shown in Figure l; the brushes 12 likewise returning to their normally displaced positions.

When such demeshing occurs, the end spring 22 will be under slight compression; consequently when the pinion leaves the fly wheel gear, the former will be snapped or given a sudden impulse to quickly shift the same clear of the fly wheel gear to prevent chamfering thereof by the fly wheel gear. This end spring 22 will also tend to prevent the pinion 15 from coming in contact with the fly wheel gear when the starting motor is idle. It will thus be apparent that the pinion 15 will have a reverse longitudinal movement when it engages the fly wheel gear and when it demeshes. In both instances it moves'in the opposite direction first to compress the inner spring 22 and then to compress the outer spring 22. Consequently when the pinion is denleshed from the fly wheel gear, the inner spring 22 will not be compressed or under tension, and for this III) reason the pinion will not be passed into interfering engagement with the fly wheel gear after it leaves the same.

I gear will be greatly reduced when the fly wheel gear runs under its own power and drives the pinion 15 especially when the motor circuit is opened. Consequently, the pinion 15 can be more easily demeshed from .the fly wheel gear. It should be noted that in this starter, the gears are demeshed after the motor circuit has been opened, and the rotation of the pinion is equal to that of the fly wheel whereby the usual drag upon the pinion is eliminated. From the foregoing,

it will be apparent that I have produced a novel form of starter which has a cranking yield-to overcome the sudden shock or impact from starting the fly wheel, and which has a cushion yield for absorbing the shock and impact when the fly wheel runs under its own power and starts to drive the pinion, and in which the pinion is readily demeshed and snapped out of engagement with the fly wheel gear.

It will also be appreciated that the direction of the slot 18 is such that there will be no tendency to demesh the pinion 15 before the motor circuit is opened. If the direction of the slot 18 were reversed the pinion 15 would be shifted rearwardly a certain amount to compress the inner spring 22 when the engine started under its own power. Such compression of the inner spring 22 would cause the pinion to rebound 1nto interfering engagement with the fly wheel gear after demeshing.

I am aware that many changes may be made, and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted hereon, otherwise than necessitated by the prior art.

I claim as my invention 1. A starting motor comprising a normally displaced armature and commutator brushes, sa d armature having an extended shaft, a pinion having an elongated hub mounted upon said-shaft, said hub having an inclined slot withxrespect to the longitudlnal axis thereof and extending from its rear end 1n the direction of rotation of said armature, said shaft having a pin engaging in said slot, and cushion springs between which said pinion and hub are confined.

2. In a starting motor, a normally displaced armature, a commutator brush carrier supported for relative rotation to said armature, a drum connected to said carrier and provided with a radially projecting stud, a stationary drum concentric with said first mentioned drum and having a helical guideway for receiving said stud, the forward end of said guideway extending longitudinally. of the axis of the motor. 3. In a starting motor, a normally displaced armature adapted to be shifted forwardlythrough magnetic flux, means com prising a stud connected to said armature, and a stationary inclined guideway for engaging said stud 'for shifting said armature to displaced position; one end of said guideway having a stud retaining recess for the purpose set forth.

4. The combination with an engine member, of a starter therefor comprising a motor having a normally displaced armature and commutator brushes, said armature havin an extended shaft, a pinion havin a hu loosely mounted upon said shaft, said sleeve and shaft having a pin and slot connection providing relative rotar and longitudinal movement when said pinion is in engagement with said engine member, and cushion means for controlling such longitudinal movement.

5. The combination with an engine member, of a starter therefor comprising a longitudinally movable shaft a driving member mounted thereon and having a pin and slot connection with said shaft, and adapted to be brought into coacting relation with said engine member, said connection causing reverse longitudinal movements of said driving member during engagement with and disengagement from said engine mem ber and cushion means for absorbing the thrust of such reverse longitudinal movements.

6. The combination with an engine mem-.

sloping guideway controlling the compression of said cushion means during the starting operaiton.

' The combination with an engine member, of a starter therefor comprising a magnetically shiftable shaft, a pinion having a hub provided with an inclined slot freely mounted upon said shaft, said shaft having a stud projecting in said guideway, cushion sprin s abutting the ends of said pinion, said s ot allowing limited longitudinal movement of said pinion when in engagement with said engine member for the purpose set forth.

8. In a starting motor, a normall displaced armature, a commutator brus carrier supported for. relative rotation with respect to said armature, a drum connected to said carrier, a second drum concentric helical guideway connection between said drums. a

9. The combination with an engine mem ber, of a starter therefor comprising a magnetically shiftablc shaft, a driving membe! having a slot and pin connection with said shaft, and adapted to be brought into coaction with said engine member, resilient means upon opposite ends of said driving member, said connection allowing said drivmg member to recede toward lnoperative posltion when said startm member starts to rotate said engine mem er and toward operative position when said engine member starts to drive said driving member.

In testimony whereof I have hereunto subscribed my name.

ODILON BRISBOIS. 

